Solar Collecting System Using a Rock Mass

ABSTRACT

A solar collecting system is incorporated into a natural rock mass having an upright face with a substantially direct exposure to the sun, for example a south facing granite cliff. A solar passage is formed in the rock mass to extend between an opening in the upright face of the rock mass and an internal collection area within the rock mass. One or more converging elements, for example solar converging lenses, are aligned with the solar passage and arranged to focus solar rays from the sun onto a target within the collection area. The target is in communication with a surrounding portion of the rock mass so as to be arranged to transfer heat from the target to the surrounding portion of the rock mass. A heat transfer fluid conduit may further be arranged to communicate a heat transfer fluid between the rock mass and an auxiliary device.

This application claims the benefit under 35 U.S.C. 119(e) of U.S. provisional application Ser. No. 61/466,111, filed Mar. 22, 2011.

FIELD OF THE INVENTION

The present invention relates to a solar collecting system in which a rock mass is arranged to be heated with solar rays to be used as a heat sink, and more particularly the present invention relates to a naturally occurring geological mass of rock is heated by solar rays converged through a converging element for subsequent use of the energy stored in the mass of rock by an auxiliary device.

BACKGROUND

The consumption of non-renewable energy sources is an increasing concern due both to the depletion of such sources as well as due to the polluting effects resulting from the consumption of typical non-renewable energy sources such as oil and coal. Accordingly there is an ever increasing desire for new methods of harnessing energy from renewable sources which are considered non-polluting which are able to meet increasing energy demands in a cost efficient manner.

U.S. Pat. No. 5,047,654 by Newman discloses a system for the collection and conversion of solar radiated power into electrical energy. The system uses a vertical mine shaft for transmitting collected solar flux from above ground heliostat fields, down to an underground insulated boiler. The boiler converts injected water into superheated steam which drives a steam turbine connected to an alternator or generator to produce electrical power. The system has limited storage capacity for storing excess heat to accommodate for differences in the amount of energy which can be harness between different times of the day and more particularly between different seasons.

U.S. Patent Application Publication No. 2009/0152869 discloses an apparatus for converting solar heat into electrical power by building a large structure with a transparent roof at the edge of any steep high mountain having a large diameter pipe connected to the roof at the top end of the structure and laid on the surface of the mountain to the top of the mountain. A fan-operated turbine-generator installed at the bottom base of the large diameter pipe generates electricity. The invention includes constructing shallow pools or reservoirs inside the structure, storing the moisture generated via humid air and condensation at the top of the mountain in a pool or water tank, installing a return pipe to the original reservoirs or pools, and installing a hydro-electric turbine-generator at the bottom of the mountain on this return pipe to generate additional electricity. This apparatus also has limited storage capacity for storing excess heat to accommodate for differences in the amount of energy which can be harness between different times of the day and more particularly between different seasons.

SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided a solar collecting system in combination with a natural rock mass having an upright face with a substantially direct exposure to the sun, the solar collector comprising:

a solar passage formed in the rock mass to extend between an opening in the upright face of the rock mass and an internal collection area in the rock mass;

a target in the collection area in communication with a surrounding portion of the rock mass so as to be arranged to transfer heat from the target to the surrounding portion of the rock mass;

at least one converging element in alignment with the solar passage and arranged to focus solar rays from the sun onto the target; and

a heat transfer fluid conduit arranged to communicate a heat transfer fluid between the surrounding portion of the rock mass and an auxiliary device so as to be arranged to transfer heat from the surrounding portion of the rock mass to the auxiliary device.

When a converging element focuses solar rays onto a target within a collection area in a natural rock mass, the rock mass is effectively used as a heat sink. When using a naturally occurring geological mass, for example a cliff face of a hard rock mountain of granite or the like, or by blasting or drilling an upright face in a mountain to have a Southern exposure in the Northern hemisphere, a large heat sink is readily available permitting storage of enough heat captured over summer months to still be used over winter months as desired. This is achieved due to the high heat capacity of the rock mass which permits the storage of sufficient heat to store heat between seasons. As the rock mass is mostly a naturally occurring deposit of rock, the solar collection system is relatively low cost compared to many other forms of storing solar energy.

The solar passage may decrease in width in a lateral direction from the upright face to the target so as to correspond in shape to a focusing plane of the solar rays focused by said at least one converging element onto the target.

The converging element is preferably supported adjacent to the upright face of the rock mass.

More preferably the converging element is supported externally of the solar passage adjacent the upright face of the rock mass.

There may be provided an enclosure about said at least one converging element when the converging element is located externally.

The converging element may comprise an array of converging lenses adjacent one another and commonly focused on the target, or more particularly one or more biconvex lenses.

Alternatively the converging element may comprise a heliostat.

Preferably the upright face of the rock mass comprises a geological cliff face, for example a geological mass of granite rock, or a blasted rock face which is substantially vertical in orientation.

In the Northern Hemisphere, preferably the upright face is oriented to face in a southern direction.

There may be provided a plurality of targets within respective collection areas at laterally spaced apart positions in the rock mass in which each target has a respective solar passage associated therewith in communication from the target to a respective opening in the upright face. In this instance, preferably at least one converging element is provided in alignment with each respective solar passage so as to be arranged to focus solar rays from the sun onto the respective target.

There may also be provided an access passage in communication between adjacent ones of the collection areas so as to be arranged to provide access between the collection areas by authorized persons.

There may further be provided a secondary passage in the rock mass which is spaced from the access passage and which extends substantially parallel to the access passage in which the secondary passage and the access passage are interconnected at longitudinally spaced positions along the access passage so as to be arranged to provide secondary access to the collection areas by authorized persons.

The access passage is preferably in communication with a respective exterior opening in the natural rock mass.

The exterior opening may be located in a secondary face of the rock mass which is separate from the upright face which has the substantially direct exposure to the sun.

There may also be provided a tracking mechanism arranged to steer said at least one converging element relative to the upright face such that said at least one converging element is arranged to remain focused on the target as the position of the sun varies throughout the day.

The target may comprise a metallic member in heat exchanging relationship with the surrounding rock mass either by: i) being in direct contact with the surrounding rock mass; or ii) using a heat exchanger in communication between the metallic member and the surrounding rock mass.

Alternatively the target may comprise an exposed portion of the rock mass within the collection area.

In some embodiments, the auxiliary device may include a greenhouse arranged to be heated by the heat transfer fluid in which the greenhouse may be located adjacent a bottom end of the upright face of the rock mass.

Alternatively the auxiliary device may comprise a steam driven electricity generator.

Some embodiments of the invention will now be described in conjunction with the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the solar collecting system according to the present invention.

FIG. 2 is a sectional view along the axis 2-2 of FIG. 1.

FIG. 3 is a sectional view along the axis 3-3 of FIG. 2.

FIG. 4 is a sectional view similar to FIG. 2 of an alternative embodiment of the target.

In the drawings like characters of reference indicate corresponding parts in the different figures.

DETAILED DESCRIPTION

Referring to the accompanying figures there is illustrated a solar collecting system generally indicated by reference numeral 10. The system 10 is used in combination with a rock mass 12 which typically comprises a naturally geological occurring deposit or mass of a hard sedimentary rock such as granite and the like which has a high heat capacity. The rock mass 12 either comprises a naturally occurring cliff face or a portion of the rock mass is blasted or otherwise drilled and formed to define the upright exposed face 14 having a southern exposure when in the northern hemisphere so as to have a substantially direct exposure to the sun. In the preferred embodiment an auxiliary upright face 16 of the rock mass is also exposed in which the auxiliary face is transverse to the exposed face 14 so as to provide access to the internal areas of the system 10. In the illustrated embodiment, the auxiliary face has a western exposure.

The system 10 includes a plurality of collection areas 18 which are horizontally spaced apart from one another in a longitudinal direction parallel to the exposed face 14 so as to be substantially evenly spaced from one another and equidistant to the exposed face. Each collection area 18 comprises a chamber locating a target 20 therein to be heated by solar rays focused thereon.

Access for the solar rays is provided to each collection area by a respective solar passage 22 extending transversely to the longitudinal direction of the rock face such that each solar passage extends between the target in the respective collection area 18 and a respective solar opening 24 formed in the face 14 of the rock mass. Typically the solar opening 24 is elongate in the longitudinal or horizontal direction. The passage 22 spans the full width of the opening at the outer end while becoming narrower in horizontal width from the exterior opening to the target area which is lower in elevation than the opening. Accordingly, each solar passage 22 is sloped inwardly at a downward inclination so as to correspond with optimal alignment with the elevation of the sun such that solar rays from the sun can directly reach the collection area.

Each solar opening 24 is associated with a respective lens array 26 comprising a horizontal row of bi-convex converging lenses 28. Each of the lenses 28 of the array 26 associated with each opening is oriented to focus the solar rays passing there through to a common focal point at the common location of the associated target in the respective collection area. Due to the focusing of the solar rays passing through the lenses supported at the exterior of the passage adjacent the opening in the face, the height of each passage can also be reduced from the greatest height at the exterior opening 24 to a smallest height adjacent the target in the collection area. The profile of the passage in both width and height can thus be arranged to substantially follow the corresponding focal plane of the lens array. As the lenses are in a single horizontal row, the height of the passages taper in height corresponding to the focusing of rays through a single lens height. In the horizontal direction of the upright face, the width becomes narrower from a combined width of the entire row of lenses at the opening to a much narrower width corresponding to the overlapping focal planes of the lenses adjacent the target.

Each lens array 26 is provided with a tracking mechanism arranged to steer the direction of the lenses relative to the upright face of the rock mass. In this manner, each of the lenses remains focused on the target as the sun is displaced across the sky following its daily cycle.

Each lens array 26 is protected by a respective solarium 30 forming a full enclosure about the array. The enclosure formed by the solarium 30 encloses the exterior opening for trapping heat within the passage as may be desired. Where it is more desirable for the solar rays to be cast directly upon the lenses, the solarium may be provided with doors which can be opened to expose the lenses. As the doors remain transparent, the suns rays can readily reach the lenses even when the doors are closed.

Each exterior opening 24 typically includes a window 31 which permits the respective passage 22 to be enclosed and selectively separated from the solarium space locating the respective lens array while still allowing passage of solar rays there through. The wall locating the window 31 therein may also include a ventilation opening which is louvered to allow the ventilation opening to be opened or closed automatically under action of a suitable controller. When opened, heated air can be communicated through the opening between the passage and the solarium. The controller opens and closes the openings to maintain the temperature within the solarium within a prescribed range without overheating the solarium from the heat built up in the collection area and surrounding rock mass. To provide access to the collection areas, an access passage 32 is provided in the form of a tunnel which extends substantially parallel to the rock face 14 in a horizontal direction so as to be connected between adjacent ones of the collection areas. The access passage may be provided only a few feet away from the exposed face 14. The tunnel may measure 25 or 30 feet for example. Suitable doors 34 permit the collection areas to remain separated from one another while selectively providing access when desired. The doors are insulated to trap heat within the collection area as desired during normal use. The passage 32 is typically arranged to provide access for persons or small vehicles when authorized. The passage 32 is typically connected to an exterior opening 36 located in the auxiliary face 16 which is the secondary face of the rock mass oriented perpendicularly to the exposed face 14 at one end thereof.

The system further includes a secondary passage 38 which is parallel to the access passage 32 but which is spaced further into the rock mass so as to be spaced farther from the exposed face 14. The secondary passage is also suitably sized to provide access to authorized persons and small vehicles for maintenance and the like. The secondary passage 38 is also connected to an exterior opening 40 in the auxiliary face of the rock mass. Typically large storage chambers 42 are also bored into the rock mass to permit storage of various equipment required to operate and maintain the collection system 10.

The secondary passage 38 is coupled to the access passage 32 by a plurality of transverse connecting passages 44 which are oriented substantially perpendicularly to the face 14 so as to communicate between the secondary passage 38 and the access passage 32 at longitudinally spaced positions such that each connecting passage 44 is located between an adjacent pair of collection areas. The insulated doors 34 in the access passage also separate the collection areas from the connecting passages 44 when desired. The exterior openings of both passages also include respective insulated doors to trap heat within the passages as may be desired. The transverse connecting passages effectively provide secondary access to the collection areas through the secondary passages 38.

Each connecting passage 44 may also connect to a respective exterior opening in the exposed face 14 between a respective adjacent pair of lens arrays 26 surrounded by respective solariums 30. A suitable insulated door also encloses the exterior opening of each connecting passage 44 in the upright face 14 so as to trap heat and selectively enclose the exterior opening 46. The location of the exterior openings of the access passage and the secondary passage 38 in an auxiliary face transverse to the exposed face 14 provides greater access for vehicles requiring ramps and the like to access the tunnels due to the tunnels typically being elevated above the valley floor at the bottom of the cliff face.

In both embodiments, the solar rays are concentrated by the converging lenses of the lens arrays 26 onto the respective targets within the respective collection areas such that the targets are heated up and communication between the targets and the surrounding portion of rock mass allows heat to be transferred from the target to the surrounding portion of rock mass which functions as a heat sink. The stored heat can then be transferred using a suitable heat transfer working fluid in communication between the surrounding portion of the rock mass and an auxiliary device so as to be arranged to transfer heat from the surrounding portion of the rock mass to the auxiliary device which may use the heat for various purposes.

In the illustrated embodiment, the auxiliary device can comprise boilers which generate steam which are fed to steam driven electrical generators to generate electricity.

In addition to or instead of the boilers, heat transfer fluid may be conveyed through suitable piping from the surrounding rock mass to a plurality of greenhouses 48 provided in an array interconnected by access roads at the floor of the valley formed at the base of the exposed upright face 14. The heat transfer fluid which is heated by the surrounding portion of the rock mass carries the heat to the greenhouse area where the heat can be released to maintain the temperature within the greenhouse space at an optimally controlled temperature permitting various forms of vegetation to be grown throughout the year even in colder climates.

Turning now specifically to FIG. 2, according to the first embodiment the target comprises a metal plate having a high melting temperature, for example titanium. The plate in this instance is either supported in direct contact with the surrounding rock mass to directly transfer the heat to the rock mass, or a suitable heat transfer fluid is in communication between the target plate and the surrounding rock mass. The surrounding air in the chamber may function as a suitable heat transfer between the plate and the surrounding rock mass while also permitting some heat to radiate directly from the plate to the surrounding rock in the chamber. Also a working fluid may be circulated through channels in the plate for rapidly cooling the plate and heating the working fluid for subsequent transfer through conduits in the surrounding rock mass to transfer the heat to the rock mass.

Turning now more particularly to the embodiment of FIG. 4, the target in this instance simply comprises the north wall of the chamber defining the collection area such that the solar rays are focused by the lenses to a common target location consisting of the rock forming the rock mass itself. The direct heating of the rock permits the heat to be directly conducted to the surrounding portion of the rock functioning as the heat sink. Heat exchanger conduits in the surrounding rock mass receive fluid circulated there through such that the fluid can be directly circulated from the surrounding rock mass directly heated by the solar rays to either the boiler driven electric generator or the greenhouse as described above.

Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense. 

1. A solar collecting system in combination with a natural rock mass having an upright face with a substantially direct exposure to the sun, the solar collector comprising: a solar passage formed in the rock mass to extend between an opening in the upright face of the rock mass and an internal collection area in the rock mass; a target in the collection area in communication with a surrounding portion of the rock mass so as to be arranged to transfer heat from the target to the surrounding portion of the rock mass; at least one converging element in alignment with the solar passage and arranged to focus solar rays from the sun onto the target; and a heat transfer fluid conduit arranged to communicate a heat transfer fluid between the surrounding portion of the rock mass and an auxiliary device so as to be arranged to transfer heat from the surrounding portion of the rock mass to the auxiliary device.
 2. The combination according to claim 1 wherein said at least one converging element is supported adjacent to the upright face of the rock mass.
 3. The combination according to claim 2 wherein the solar passage decreases in width in a lateral direction from the upright face to the target so as to correspond in shape to a focusing plane of the solar rays focused by said at least one converging element onto the target.
 4. The combination according to claim 1 wherein said at least one converging element is supported externally of the solar passage adjacent the upright face of the rock mass.
 5. The combination according to claim 4 wherein there is provided an enclosure about said at least one converging element.
 6. The combination according to claim 1 wherein said at least one converging element comprises an array of converging lenses adjacent one another and commonly focused on the target.
 7. The combination according to claim 1 wherein said at least one converging element comprises a biconvex lens.
 8. The combination according to claim 1 wherein said at least one converging element comprises a heliostat.
 9. The combination according to claim 1 wherein the upright face of the rock mass comprises a geological cliff face.
 10. The combination according to claim 1 wherein the upright face comprises a blasted rock face which is substantially vertical in orientation.
 11. The combination according to claim 1 wherein the rock mass comprises a geological mass of granite rock.
 12. The combination according to claim 1 wherein the upright face is oriented to face in a southern direction.
 13. The combination according to claim 1 wherein there is provided a plurality of targets within respective collection areas at laterally spaced apart positions in the rock mass, each target having a respective solar passage associated therewith in communication from the target to a respective opening in the upright face and at least one converging element in alignment with the respective solar passage so as to be arranged to focus solar rays from the sun onto the respective target.
 14. The combination according to claim 13 wherein there is provided an access passage in communication between adjacent ones of the collection areas so as to be arranged to provide access between the collection areas by authorized persons.
 15. The combination according to claim 14 wherein there is provided a secondary passage in the rock mass which is spaced from the access passage and which extends substantially parallel to the access passage, the secondary passage and the access passage being interconnected at longitudinally spaced positions along the access passage so as to be arranged to provide secondary access to the collection areas by authorized persons.
 16. The combination according to claim 14 wherein the access passage is in communication with a respective exterior opening in the natural rock mass.
 17. The combination according to claim 14 wherein the exterior opening is located in a secondary face of the rock mass which is separate from the upright face which has the substantially direct exposure to the sun.
 18. The combination according to claim 1 wherein there is provided a tracking mechanism arranged to steer said at least one converging element relative to the upright face such that said at least one converging element is arranged to remain focused on the target as the position of the sun varies throughout the day.
 19. The combination according to claim 1 wherein the auxiliary device comprises a greenhouse arranged to be heated by the heat transfer fluid.
 20. The combination according to claim 1 wherein the target comprises a metallic member in heat exchanging communication with the surrounding rock mass. 